Debian 9 + VirtualBox, why did the network stop working?

Question

Debian

The question is next. Previously, when I used Debian 7 and 8 (Jessie and Wheezy) through Oracle Virtualbox, I set up the network like this:
1) The first adapter is NAT
2) The second one is Host-Only (aka Virtual Host Adapter)
3) in /etc/network/ interfaces of the virtual machine wrote the following config:

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# NAT
auto eth0
allow-hotplug eth0
iface eth0 inet dhcp

# Host-only adapter
auto eth1
iface eth1 inet static
address 192.168.56.2
netmask 255.255.255.0

4) Rebooted and everything worked. From the host, the virtual machine is available at 192.168.56.2, the Internet works in it, and the rest of the machines on the network do not see it.
Now I installed Debian 9, did everything exactly the same, and ... it does not work at all.
$ ip a produces the following

Answer 1

Are the interface names in /etc/network/interfaces correct?